Preheat the oven to 400°F. Heat olive oil in a large oven-safe pot over medium-high heat.
Pat the chicken thighs dry and season both sides with salt and pepper. Place them skin-side down in the hot pot, allowing space between each piece. Cook until the skin turns golden brown, then flip and cook briefly on the other side. Transfer the chicken to a plate.
Carefully remove excess fat from the pot, leaving a small amount behind. Add the chopped onion, carrots, and celery, and sauté until slightly softened. Stir in the garlic and cook until fragrant.
Pour in the chicken broth and lemon juice, then bring the mixture to a boil. In a small bowl, combine Italian seasoning and paprika, then season the chicken with this mixture.
Add the rice to the pot and stir briefly to distribute it evenly. Remove the pot from heat and place the chicken thighs on top of the rice.
Cover the pot with a tight-fitting lid and transfer it to the oven. Bake until the rice is tender and the chicken is fully cooked through.
Remove the chicken from the pot, stir in the chopped parsley, and gently fluff the rice. Return the chicken on top or serve alongside the rice while warm.